Nanoemulsion based on ethylene oxide and propylene oxide block copolymers and its uses in the cosmetics, dermatological and/or ophthalmological fields

ABSTRACT

A nanoemulsion comprising an oily phase dispersed in an aqueous phase and having oil globules with a number-average size of less than 100 mm, which dispersion is facilitated by a surfactant comprised of polyethylene oxide and polypropylene oxide blocks, the oily phase comprising at least one oil having a molecular weight of greater than 400 and wherein the ratio by weight of the amount of oily phase to the amount of surfactant ranges from 2 to 10.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a nanoemulsion based on asurfactant having polyethylene oxide and polypropylene oxide blocks andon at least one oil having a molecular weight of greater than 400, theratio by weight of the amount of oily phase to the amount of surfactantranging from 2 to 10. The present invention also relates to a processfor the preparation of the nanoemulsion and to its uses in thecosmetics, dermatological and/or ophthalmological fields. Thisnanoemulsion is stable on storage and can comprise large amounts of oilwhile retaining good transparency and while having good cosmeticproperties.

[0003] 2. Description of the Background

[0004] Nanoemulsions are oil-in-water emulsions, the oil globules ofwhich have a very fine particle size, that is to say a number-averagesize of less than 100 nm. They are generally manufactured by mechanicalfragmentation of an oily phase in an aqueous phase in the presence of asurfactant. In the case of nanoemulsions, the very small size of theoily globules is obtained in particular by virtue of at least one passthrough a high-pressure homogenizer. The small size of the globulesconfers on them cosmetically advantageous properties which distinguishthem from conventional emulsions: they are transparent and exhibit auniquely different texture. They can also carry active principles moreefficiently.

[0005] Transparent microemulsions are known in the art. In contrast tonanoemulsions, microemulsions are not, strictly speaking, emulsions;they are transparent solutions of micelles swollen by oil, which oil isgenerally a very-short-chain oil such as hexane or decane, and issolubilized by virtue of the joint presence of a significant amount ofsurfactants and of cosurfactants which form the micelles. The size ofthe swollen micelles is very small because of the small amount of oilwhich they can solubilize. This very small size of the micelles is thecause of their transparency, as with nanoemulsions. However, in contrastto nanoemulsions, microemulsions are spontaneously formed by mixing theconstituents, without contributing mechanical energy other than simplemagnetic stirring. The major disadvantages of microemulsions are relatedto their high proportion of surfactants, leading to intolerance andresulting in a sticky feel during application to the skin. Furthermore,their formulation range is generally very narrow and their temperaturestability very limited.

[0006] In addition, nanoemulsions are known in the art which comprise anamphiphilic lipid phase composed of phospholipids, water and oil. Theseemulsions exhibit the disadvantage of being unstable on storage atconventional storage temperatures, i.e., from 0 to 45° C. They lead toyellow compositions and produce rancid smells which develop afterseveral days of storage.

[0007] Nanoemulsions stabilized by a lamellar liquid crystal coating,obtained by the combination of a hydrophilic surfactant and of alipophilic surfactant, are also known. However, these combinations areproblematic to prepare. Furthermore, the nanoemulsions obtained exhibita waxy and film-forming feel which is not very pleasant for the user.

[0008] Furthermore, EP 0 728 460 discloses nanoemulsions which are basedon fluid non-ionic amphiphilic lipids. However, these nanoemulsionsexhibit the disadvantage of having a sticky effect during application tothe skin. A need, therefore, continues to exist for nanoemulsions whichhave neither the disadvantages of those of the prior art nor thedisadvantages of microemulsions.

SUMMARY OF THE INVENTION

[0009] Accordingly, one object of the present invention is to provide anonoemulsion which exhibits all of the advantages of known nanoemulsionswithout their disadvantages.

[0010] Briefly, this object and other objects of the present inventionas hereinafter will become more readily apparent can be attained by ananoemulsion comprising an oily phase dispersed in an aqueous phase andhaving oil globules with a number-average size of less than 100 nm,which dispersion is facilitated by a surfactant comprised ofpolyethylene oxide and polypropylene oxide blocks, the oily phasecomprising at least one oil having a molecular weight of greater than400 and wherein the ratio by weight of the amount of oily phase to theamount of surfactant ranges from 2 to 10.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The nanoemulsions of the invention generally have a transparentto bluish appearance. Their transparency is measured by a transmittancecoefficient at 600 nm ranging from 10 to 90% or else by a turbidityranging from 60 to 600 NTU, preferably from 70 to 300 NTU, whichturbidity is measured with a Hach Model 2100 P portable turbidimeter.

[0012] The oil globules of the nanoemulsions of the invention have anumber-average size of less than 100 nm, preferably ranging from 20 to75 nm, more preferably from 40 to 60 nm. The decrease in the size of theglobules makes it possible to promote the penetration of the activeprinciples into the surface layers of the skin (carrier effect).

[0013] The surfactant which can be used in the nanoemulsion of theinvention is selected from ethylene oxide and propylene oxide blockcopolymers, and their mixtures, and, preferably, the nanoemulsion of theinvention is devoid of any surfactant other than ethylene oxide andpropylene oxide block copolymers.

[0014] The ethylene oxide and propylene oxide block copolymers which canbe used as surfactant in the nanoemulsion of the invention can beselected, in particular, from the block copolymers of formula (I):

HO(C₂H₄O)_(x)(C₃H₆O)_(y)(C₂H₄O)_(z)H   (I)

[0015] wherein x, y and z are integers such that x+z ranges from 2 to100 and y ranges from 14 to 60, and their mixtures, and moreparticularly from the block copolymers of formula (I) having an HLBranging from 2 to 16.

[0016] These block copolymers can be selected, in particular, frompoloxamers and in particular from Poloxamer 231, such as the productsold by ICI under the name Pluronic L81, of formula (I) where x=z=6 andy=39 (HLB 2); Poloxamer 282, such as the product sold by ICI under thename Pluronic L92, of formula (I) where x=z=10 and y=47 (HLB 6); andPoloxamer 124, such as the product sold by ICI under the name PluronicL44, of formula (I) where x=z=11 and y=21 (HLB 16).

[0017] The amount of surfactant in the nanoemulsion of the invention canrange, for example, from 0.2 to 15% by weight, preferably from 1 to 8%by weight with respect to the total weight of the nanoemulsion.

[0018] The ratio by weight of the amount of the oily phase to the amountof surfactant ranges from 2 to 10, preferably from 3 to 6. The term

amount of oily phase

is understood here to mean the total amount of the constituents of thisphase without including the amount of surfactant.

[0019] The nanoemulsion of the invention comprises at least one oil witha molecular weight of greater than 400. Oils with a molecular weight ofgreater than 400 can be selected from oils of animal or vegetableorigin, mineral oils, synthetic oils and silicone oils, and theirmixtures. Suitable oils of this type, of, for example, include isocetylpalmitate, isocetyl stearate, avocado oil and jojoba oil.

[0020] In addition, the oily phase can optionally comprise other oilsand, in particular, oils having a molecular weight of less than 400.These oils are also selected from oils of animal and vegetable origin,mineral oils, synthetic oils and silicone oils. Suitable oils with amolecular weight of less than 400 include isododecane, isohexadecane,volatile silicone oils, isopropyl myristate, isopropyl palmitate andC₁₁-C₁₃ isoparaffin.

[0021] The oily phase can also comprise fatty substances other than theoils indicated above, such as fatty alcohols, for example stearyl, cetyland behenyl alcohols, fatty acids, for example stearic, palmitic andbehenic acids, oils of the fluorinated type, waxes, gums and theirmixtures.

[0022] The nanoemulsions of the invention comprise an amount of oilyphase preferably ranging from 2 to 40% and better still from 5 to 30% byweight with respect to the total weight of the nanoemulsion, theproportion of oil(s) having a molecular weight of greater than 400preferably representing at least 40% by weight of the oily phase.

[0023] According to a specific embodiment of the invention, thenanoemulsion of the invention additionally comprises one or more ionicamphiphilic lipids.

[0024] The ionic amphiphilic lipids which can be used in thenanoemulsions of the invention are preferably selected from the group ofanionic amphiphilic lipids, cationic amphiphilic lipids andalkylsulphonic derivatives.

[0025] The anionic amphiphilic lipids can be more particularly selectedfrom the group of:

[0026] the alkaline salts of dicetyl and dimyristyl phosphate;

[0027] the alkaline salts of cholesterol sulfate;

[0028] the alkaline salts of cholesterol phosphate;

[0029] lipoamino acids and their salts, such as mono- and disodiumacylglutamates, such as the disodium salt of N-stearoyl-L-glutamic acidsold under the name Acylglutamate HS21 by Ajinomoto;

[0030] the sodium salts of phosphatidic acid;

[0031] phospholipids.

[0032] The alkylsulfonic derivatives can more particularly be selectedfrom the group of alkylsulfonic derivatives of formula (I):

[0033] wherein R represents an alkyl radical comprising from 16 to 22carbon atoms, in particular the C₁₆H₃₃ and C₁₈H₃₇ radicals, taken as amixture or separately, and M is an alkali metal, such as sodium.

[0034] The cationic amphiphilic lipids can more particularly be selectedfrom the group of quaternary ammonium salts, fatty amines and theirsalts.

[0035] The quaternary ammonium salts include, for example:

[0036] those which exhibit the following formula (II):

[0037] wherein the R₁ to R₄ radicals, which can be identical ordifferent, represent a linear or branched aliphatic radical comprisingfrom 1 to 30 carbon atoms or an aromatic radical, such as aryl oralkylaryl. The aliphatic radicals can comprise heteroatoms, such as, inparticular, oxygen, nitrogen, sulfur and halogens. The aliphaticradicals include, for example, alkyl, alkoxy, polyoxy(C₂-C₆)alkylene,alkylamido, (C₁₂-C₂₂)alkylamido(C₂-C₆)alkyl, (C₁₂-C₂₂ )alkyl acetate andhydroxyalkyl radicals comprising approximately from 1 to 30 carbonatoms; X is an anion selected from the group of the halides, phosphates,acetates, lactates, (C₂-C₆)alkyl sulfates, and alkyl- oralkylarylsulfonates. Preference is given, as quaternary ammonium saltsof formula (II), to, on the one hand, tetraalkylammonium chlorides, suchas, for example, dialkyldimethylammonium and alkyltrimethylammoniumchlorides in which the alkyl radical comprises approximately from 12 to22 carbon atoms, in particular behenyltrimethylammonium,distearyldimethylammonium, cetyltrimethylammonium andbenzyldimethylstearylammonium chlorides, or alternatively,stearamidopropyldimethyl(myristyl acetate)ammonium chloride, sold underthe name

CERAPHYL 70

by Van Dyk.

[0038] imidazolinium quaternary ammonium salts, such as, for example,those of formula (III):

[0039] wherein R₅ represents an alkenyl or alkyl radical comprising from8 to 30 carbon atoms, for example derived from tallow fatty acids; R₆represents a hydrogen atom, an alkyl radical comprising from 1 to 4carbon atoms or an alkenyl or alkyl radical comprising from 8 to 30carbon atoms; R₇ represents an alkyl radical comprising from 1 to 4carbon atoms; R₈ represents a hydrogen atom or an alkyl radicalcomprising from 1 to 4 carbon atoms; and X is an anion selected from thegroup of the halides, phosphates, acetates, lactates, alkyl sulfates, oralkyl- and alkylarylsulfonates. R₅ and R₆ preferably denote a mixture ofalkenyl or alkyl radicals comprising from 12 to 21 carbon atoms, forexample derived from tallow fatty acids, R₇ preferably denotes a methylradical and R₈ preferably denotes hydrogen. Such a product is, forexample, sold under the name

REWOQUAT W 75

by Rewo.

[0040] quaternary diammonium salts of formula (IV):

[0041] wherein R₉ denotes an aliphatic radical comprising approximatelyfrom 16 to 30 carbon atoms; R₁₀, R₁₁, R₁₂, R₁₃ and R₁₄ are selected fromhydrogen and an alkyl radical comprising from 1 to 4 carbon atoms; and Xis an anion selected from the group of the halides, acetates,phosphates, nitrates and methyl sulfates.

[0042] Such quaternary diammonium salts comprise in particularpropanetallowdiammonium dichloride.

[0043] According to a preferred embodiment of the invention, a lipoaminoacid is used as ionic amphiphilic lipid.

[0044] The ionic amphiphilic lipids can be introduced into one or theother phase of the nanoemulsion. When they are present in thenanoemulsion of the invention, they can be used in concentrationspreferably ranging from 0.01 to 5% by weight and more particularly from0.25 to 1% by weight with respect to the total weight of thenanoemulsion.

[0045] The emulsions in accordance with the present invention cancomprise additives for improving the transparency of the formulation.

[0046] These additives are preferably selected from the group of:

[0047] lower alcohols comprising from 1 to 8 carbon atoms and moreparticularly from 2 to 6 carbon atoms, such as ethanol;

[0048] glycols, such as glycerol, propylene glycol, 1,3-butylene glycol,dipropylene glycol, pentylene glycol, isoprene glycol and polyethyleneglycols comprising from 4 to 16, preferably from 8 to 12 ethylene oxideunits;

[0049] sugars, such as glucose, fructose, maltose, lactose or sucrose.

[0050] These additives can be used as a mixture. When they are presentin the nanoemulsion of the invention, they can be used at concentrationspreferably ranging from 0.01 to 3% by weight with respect to the totalweight of the nanoemulsion and better still from 5 to 20% by weight withrespect to the total weight of the nanoemulsion. The amount ofalcohol(s) and/or of sugar(s) preferably ranges from 5 to 20% by weightwith respect to the total weight of the nanoemulsion and the amount ofglycol(s) preferably ranges from 5 to 15% by weight with respect to thetotal weight of the nanoemulsion.

[0051] In addition, the use of the alcohols as defined above atconcentrations greater than or equal to 15% by weight makes it possibleto obtain preservative-free emulsions.

[0052] The nanoemulsions defined above can be used in any field wherethis type of composition is useful. They can constitute in particularcompositions for topical use and in particular cosmetic ordermatological compositions. They can also be used as ophthalmicvehicles. In addition, they can constitute, in the pharmaceutical field,a pharmaceutical composition which can be administered orally,parenterally or transcutaneously.

[0053] Another aspect of the invention is, therefore, a composition fortopical use, which comprises a nanoemulsion as defined above.

[0054] A composition for topical or pharmaceutical use comprises aphysiologically acceptable medium, that is to say compatible with theskin, mucous membranes, scalp, eyes and/or hair.

[0055] Another aspect of the invention is an ophthalmic vehicle, whichcomprises a nanoemulsion as defined above.

[0056] Still another aspect of the invention is a pharmaceuticalcomposition, which comprises a nanoemulsion as defined above.

[0057] The nanoemulsions of the invention can comprise water-soluble orfat-soluble active principles having a cosmetic, dermatological orophthalmic activity. The fat-soluble active principles are in the oilyglobules of the emulsion, whereas the water-soluble active principlesare in the aqueous phase of the emulsion. Suitable examples of activeprinciples include vitamins, such as vitamin E, and their derivativesand in particular their esters, provitamins, such as panthenol,humectants and sun-screen agents.

[0058] Suitable ophthalmic active principles include, for example,antiglaucoma agents, such as betaxolol; antibiotics, such as acyclovir;antiallergics; anti-inflammatory agents, such as ibuprofen and itssalts, diclofenac and its salts, or indomethacin; or antiviral agents.

[0059] The nanoemulsions of the invention can be provided in the form ofa lotion, serum, cream, milk or toilet water and can comprise adjuvantscommonly used in the cosmetics, dermatological and ophthalmic fields,such as, for example, gelling agents, preservatives, antioxidants andfragrances. They can also be provided in the form of an eye lotion, inparticular for ophthalmological applications.

[0060] Suitable gelling agents which can be used, include cellulosederivatives, algal derivatives, natural gums and synthetic polymers,such as polymers and copolymers of carboxyvinyl acids, for example,those sold under the name Carbopol by Goodrich.

[0061] Another aspect of the invention is a process for the preparationof a nanoemulsion as defined above, this process comprising the mixingof the aqueous phase and the oily phase with vigorous stirring at atemperature ranging from 10 to 80° C. and then a homogenization of themixture at a pressure preferably ranging from 6×10⁷ Pa to 18×10⁷ Pa(high-pressure homogenization). The shearing preferably ranges from2×10⁶ s⁻¹ to 5×10⁸ s⁻¹, better still from 1×10⁸ s⁻¹ to 3×10⁸ s⁻¹ (s⁻¹signifies second⁻¹).

[0062] The nanoemulsion of the invention can be used, for example, forcaring, for treating or making-up the skin, face and/or scalp.

[0063] Yet another aspect of the invention is the cosmetic use of thenanoemulsion as defined above for caring for, treating and/or making-upthe skin, face and/or scalp.

[0064] In addition, the nanoemulsion of the invention can also be usedfor caring for and/or treating the hair. The invention makes it possibleto obtain a deposit of oil on the hair, which renders the latterglossier and more resistant to styling, without, however, making itlank. It also makes it possible, as a pretreatment, to improve theeffects of dyeing or permanent waving of the hair.

[0065] Another aspect of the invention is the cosmetic use of thenanoemulsion as defined above for caring for and/or treating the hair.

[0066] The nanoemulsion of the invention makes possible, in particular,good moisturizing of the skin, mucous membranes and/or scalp and isparticularly suited to the treatment of dry skin.

[0067] Another aspect of the invention is, therefore, a cosmetic processfor caring for and/or moisturizing the skin, mucous membranes and/orscalp, wherein the nanoemulsion as defined above is applied to the skin,mucous membranes and/or scalp.

[0068] The invention also relates to the use of the nanoemulsion of theinvention in the manufacture of a dermatological composition intendedfor the treatment of dry skin.

[0069] Finally, the invention also relates to the use of thenanoemulsion of the invention in the manufacture of an ophthalmologicalcomposition.

[0070] Having now generally described this invention, a furtherunderstanding can be obtained by reference to certain specific exampleswhich are provided herein for purposes of illustration only and are notintended to be limiting unless otherwise specified. The amounts shownbelow are in % by weight.

EXAMPLES

[0071] Example 1: Fluid make-up remover Oily phase: Disodium salt ofN-stearoyl-L-glutamic acid (Acylglutamate 0.5% HS21 from Ajinomoto)Poloxamer 124 (Pluronic L44 from ICI) 4.5% Isocetyl stearate (M.W. =508) 10% Isododecane (M.W. = 170) 5% Aqueous phase: Glycerol 5%Dipropylene glycol 10% Water 65%

[0072] A transparent nanoemulsion is obtained, the size of the globulesof which is 46 nm and the turbidity of which is 130 NTU.

[0073] Example 2: Make-up removing gel Oily phase: Poloxamer 231(Pluronic L81 from ICI) 4.5% Disodium salt of N-stearoyl-L-glutamic acid(Acylglutamate 0.5% HS21 from Ajinomoto) Isocetyl stearate (M.W. = 508)16% Isopropyl myristate (M.W. = 270) 4% Aqueous phase: Glycerol 5%Dipropylene glycol 10% Water 60%

[0074] A gelled transparent nanoemulsion is obtained, the size of theglobules of which is 54 nm and the turbidity of which is 256 NTU.

[0075] Example 3: Eye lotion Oily phase: Poloxamer 282 (Pluronic L92from ICI) 0.75% Disodium salt of N-stearoyl-L-glutamic acid(Acylglutamate 0.08% HS21 from Ajinomoto) Soybean oil (M.W. of the orderof 900) 1.67% Isopropyl myristate (M.W. = 270) 0.83% Aqueous phase:Glycerol 0.83% Dipropylene glycol 1.67% Water q.s. for 100%

[0076] A transparent nanoemulsion is obtained, the size of the globulesof which is 44 nm and the turbidity of which is 110 NTU.

[0077] The disclosure of French priority Application Number 9900031filed Jan. 1, 1999 is hereby incorporated by reference into the presentapplication.

[0078] Obviously, numerous modifications and variations of the presentinvention are possible in light of the above teachings. It is,therefore, to be understood that within the scope of the appendedclaims, the invention may be practised otherwise than as specificallydescribed herein

What is claimed as new and is intended to be secured by Letters Patentis:
 1. A nanoemulsion comprising an oily phase dispersed in an aqueousphase and having oil globules with a number-average size of less than100 nm, which dispersion is facilitated by a surfactant comprised ofpolyethylene oxide and polypropylene oxide blocks, the oily phasecomprising at least one oil having a molecular weight of greater than400 and wherein the ratio by weight of the amount of oily phase to theamount of surfactant ranges from 2 to
 10. 2. The nanoemulsion accordingto claim 1, which has a turbidity ranging from 60 to 600 NTU.
 3. Thenanoemulsion according to claim 1, wherein the amount of surfactantranges from 0.2 to 15% by weight with respect to the total weight of thenanoemulsion.
 4. The nanoemulsion according to claim 3, wherein theamount of surfactant ranges from 1 to 8% by weight with respect to thetotal weight of the nanoemulsion.
 5. The nanoemulsion according to claim1, wherein the ratio by weight of the amount of oily phase to the amountof surfactant ranges from 3 to
 6. 6. The nanoemulsion according to claim1, wherein the oil globules have an average size ranging from 20 to 75nm.
 7. The nanoemulsion according to claim 1, wherein the surfactant isa block copolymer of formula (I) having an HLB ranging from 2 to 16:HO(C₂H₄O)_(x)(C₃H₆O)_(y)(C₂H₄O)_(z)H   (I) wherein x, y and z areintegers such that x+z ranges from 2 to 100 and y ranges from 14 to 60,and mixtures of individual surfactants within the scope of the formula.8. The nanoemulsion according to claim 1, wherein the surfactant isselected from the group consisting of Poloxamer 231, Poloxamer 282,Poloxamer 124 and their mixtures.
 9. The nanoemulsion according to claim1, wherein the oil with a molecular weight of greater than 400 isselected from the group consisting of oils of animal or vegetableorigin, mineral oils, synthetic oils and silicone oils, and theirmixtures.
 10. The nanoemulsion according to claim 1, wherein the oilyphase additionally comprises at least one oil having a molecular weightof less than
 400. 11. The nanoemulsion according to claim 1, wherein theoily phase comprises at least 40% by weight of oil(s) having a molecularweight of greater than 400 with respect to the total weight of the oilyphase.
 12. The nanoemulsion according to claim 1, wherein the amount ofoily phase ranges from 2 to 40% by weight with respect to the totalweight of the nanoemulsion
 13. The nanoemulsion according to claim 1,wherein the nanoemulsion additionally comprises at least one ionicamphiphilic lipid selected from the group consisting of anionicamphiphilic lipids, cationic amphiphilic lipids and alkylsulfonicderivatives.
 14. The nanoemulsion according to claim 13, wherein theionic amphiphilic lipids are selected from the group consisting of: thealkaline salts of dicetyl and dimyristyl phosphate; the alkaline saltsof cholesterol sulfate; the alkaline salts of cholesterol phosphate; thesalts of lipoamino acids; the sodium salts of phosphatidic acid;phospholipids; the alkylsulfonic derivatives of formula (I):

wherein R represents C₁₆-C₂₂ alkyl radicals, taken as a mixture orseparately, and M is an alkali metal, a quaternary ammonium ion, a fattyamine or a salt thereof, and their mixtures.
 15. The nanoemulsionaccording to claim 13, wherein the amount of ionic amphiphilic lipid(s)ranges from 0.01 to 5% by weight with respect to the total weight of thenanoemulsion.
 16. The nanoemulsion according to claim 1, wherein thenanoemulsion comprises an additive which makes it possible to improvethe transparency of the composition and is selected from the groupconsisting of lower alcohols, glycols, sugars and their mixtures. 17.The nanoemulsion according to claim 16, wherein the additive is presentin a concentration ranging from 5 to 20% by weight with respect to thetotal weight of the nanoemulsion.
 18. The nanoemulsion according toclaim 1, which further comprises a cosmetic, dermatological orophthalmological active principle.
 19. A composition for topicalapplication which comprises the nanoemulsion according to claim
 1. 20.An ophthalmic vehicle, which comprises the nanoemulsion according toclaim 1
 21. A pharmaceutical composition, which comprises thenanoemulsion according to claim
 1. 22. A method of cosmetically treatingskin, comprising: applying the nanoemulsion according to claim 1 to theskin in order to care for, treat and/or make-up the skin of the body,face and/or scalp.
 23. A method of cosmetically treating hair,comprising: applying the nanoemulsion according to claim 1 to the hairin order to care for and/or treat the hair.
 24. A method of cosmetictreatment, comprising: applying the nanoemulsion according to claim 1 tothe skin, mucous membranes and/or scalp for the care of and/or themoisturizing of the skin, mucous membranes and/or scalp.
 25. A method ofmanufacturing a dermatological composition, comprising: formulating thecomposition with the nanoemulsion according to claim 1 for the treatmentof dry skin.
 26. A method of manufacturing a ophthalmologicalcomposition, comprising: formulating the composition with thenanoemulsion according to claim
 1. 27. A process for the preparation ofthe nanoemulsion of claim 1, which comprises: mixing said aqueous phaseand said oily phase with vigorous stirring at an ambient temperatureranging from 10 to 80° C., and then homogenizing the mixture at apressure ranging from 6×10⁷ Pa to 18×10⁷ Pa.
 28. The process accordingto claim 27, wherein the shearing ranges from 2×10⁶ s⁻¹ to 5×10⁸ s⁻¹.